Generate series of integers with random start and end SQL Oracle - sql

Question

I am trying to generate a series of integers that go from a random start-point until a random (greater) end-point. Furthermore, I would like to do this as a window function, so I could use this in a OVER (PARTITION BY ) statement.
Basically I'm trying to select random hours (from 1-24), but in a random way and also consecutively, and do this for each client (which is why I suggest an OVER (PARTITION BY client) statement, but I'm open for other ideas.
I am trying to use:
SELECT
T1.HOURS
FROM (
SELECT
LEVEL HOURS
FROM DUAL
CONNECT BY
LEVEL <= 24
) T1,
(
SELECT
INIT,
LEAST(INIT + LENGTH, 24) FIN
FROM (
SELECT
ROUND(DBMS_RANDOM.VALUE(1, 24)) INIT,
ROUND(DBMS_RANDOM.VALUE(1, 24)) LENGTH
FROM DUAL
) T0
) T2
WHERE
T1.HOURS >= T2.INIT AND
T1.HOURS <= T2.FIN;
But the result is unfortunately non-consecutive orders.
|hours|
|-----|
|17|
|18|
|20|
|24|
The code is simply nor working because the table T0 (which is the one that filters the initial INIT and final FIN value) is being replicated for each row.
This is a desired result:
client
hours
1
4
1
5
1
6
1
7
2
14
2
15
3
13
3
14
3
15
3
16
3
17
3
18
3
19
3
20
3
21
In the desired result a consecutive list is selected for each client, with a random start and end point.

Answer 1

In Oracle, you can use a correlated LATERAL join:
SELECT c.id,
h.hours
FROM ( SELECT id,
FLOOR(DBMS_RANDOM.VALUE(1, 25)) AS bound1,
FLOOR(DBMS_RANDOM.VALUE(1, 25)) AS bound2
FROM clients
) c
CROSS JOIN LATERAL (
SELECT LEAST(bound1, bound2) + LEVEL - 1 AS hours
FROM DUAL
CONNECT BY LEVEL <= ABS(bound1 - bound2) + 1
) h;
Then, for the sample data:
CREATE TABLE clients (id) AS
SELECT LEVEL FROM DUAL CONNECT BY LEVEL <= 3;
May (randomly) output:
ID
HOURS
1
7
1
8
1
9
1
10
2
19
2
20
2
21
2
22
2
23
2
24
3
6
3
7
3
8
3
9
3
10
3
11
3
12
3
13
3
14
3
15
3
16
fiddle